Brake releasing device for a railway air brake system



Nov. 25, 1969 M. E. cooK 3,430,337

I I BRAKE RELEASING DEVICE FOR A RAILWAY AIR BRAKE SYSTEM Filed July 2, 1968 I N VEN TOR: lWfiew/v E. (00K U.S. Cl. 303-72 United States Patent ()flice 3,480,337 Patented Nov. 25, 1969 3,480,337 BRAKE RELEASING DEVICE FOR A RAILWAY AIR BRAKE SYSTEM Marvin E. Cook, 3800 Creekside Drive, Nashville, Tenn. 37211 Filed July 2, 1968, Ser. No. 741,949 Int. Cl. B60t /46 10 Claims ABSTRACT OF THE DISCLOSURE A brake releasing device for a railway air brake system including a bleeder line communicating the train line with the brake cylinder and an auxiliary line communicating the auxiliary reservoir and the triple valve, a check valve in the bleeder line normally closing the bleeder line when the train line pressure is normal and adapted to open the bleeder line when the brake cylinder pressure exceeds the train line pressure, and an auxiliary valve adapted to open the auxiliary line when the train line pressure is at least sufficient to actuate the triple valve and adapted to close the auxiliary valve when the train line pressure is less than suflicient for actuating the triple valve.

Background of the invention This invention relates to an improved mechanism for releasing the brake in a railway air brake system, and more particularly to an improved valve means for bleeding the brake cylinder.

Under the present conventional means of operating railway air brake systems, including a train line, brake mechanism, triple valve and an auxiliary reservoir, the brakes may be set and released at will, so long as all the cars are coupled together and to the air compressor and the controls in the railway locomotive. However, when a car, or a train of cars, is isolated on a track or siding and disconnected from the locomotive, the brakes are automatically set because of the resultant reduction in the train line pressure. The car or train cannot be moved until either its train line is reconnected and recharged from the locomotive air compressor or the conventional bleeder valve located on the triple valve is manually opened to exhaust the auxiliary reservoir, to release the brakes.

For ordinary local switching operations, the cars are moved by smaller locomotives or switch'engines. However, before the cars can be moved, each auxiliary reservoir must be exhausted by manually opening the bleeder valve. In a train of 25 or 30 isolated cars, the release of the brakes on each individual car by exhausting the reservoir is quite time-consuming. If the train line of the car is coupled to the brake control and air compressor of the switch engine and charged with normal operating pressure, the brake will remain released only so long as the switch engine remains coupled to the car. However, in humping the cars in a switching yard, the switch engine pushes the cars over a rise in the track and they are selectively directed or switched to freely roll to the desired track by gravity. Once the switch engine becomes uncoupled from Summary of the invention This invention is an improved system for automatically releasing the brake mechanism in a railway air brake system after the train line has been exhausted. The device includes a check valve in a bleeder line connecting the brake cylinder and the train line which is normally closed when the train line pressure is normal, but is adapted to be opened when the train line pressure is lower than the pressure in the brake cylinder, and particularly when the train line pressure is exhausted. The device also includes an auxiliary valve in the auxiliary line connecting the auxiliary reservoir and the triple valve, which is normally open when the train line pressure is normal, but is responsive to the train line pressure so that when the train line pressure is reduced below a certain value, the auxiliary valve begins to slowly close in order to preserve the air pressure in the auxiliary reservoir. The device also includes a timing valve associated with the check valve so that when the check valve is open, compressed air is bled slowly from the brake cylinder so that the brakes will remain set for a predetermined period of time. The device also includes a brake-holding valve also responsive to the train line pressure to normally open the bleeder line, but which is adapted to be actuated by a separate source of compressed air for closing the bleeder line in order to maintain the brakes set until the train line pressure is restored to normal.

One object of this invention is to provide means for automatically releasing the brake mechanism in an isolated railway car, or a train of railway cars, after it has been uncoupled from a locomotive switch engine.

Another object of this invention is to provide means for automatically releasing the brake mechanism in an isolated railway car at a predetermined time after the car has been uncoupled.

A further object of this invention is to provide a novel valve for automatically releasing the brake mechanism of an uncoupled railway car, and simultaneously to slowly close the air passage between the auxiliary reservoir and the triple valve.

Another object of this invention is to provide a novel valve for automatically releasing the brake mechanism in an isolated railway car after the train line has been uncoupled, in which the valve may be easily mounted upon the triple valve without interfering with the normal functions or couplings of the triple valve with the other parts of the brake mechanism.

Brief description of the drawings FIG. 1 is a schematic view of the invention as applied to a conventional railway air brake system of a single car;

FIG. 2 is a side elevational view of a release valve made in accordance with this invention mounted upon a conventional AB valve;

FIG. 3 is a section taken along the line 3-3 of FIG. 2; and I FIG. 4 is a top plan view of the release valve disclosed in FIG. 2, with associated parts shown in section.

Description of the preferred embodiment Referring now to the drawings in more detail, FIG. 1 discloses a section of a train line 10, the associated brake mechanism 11, the triple valve or AB valve 12, and the auxiliary reservoirs 13 and 13' for a single railway car 14, shown in phantom. The brake mechanism 11 includes a brake cylinder 16, in which slida-bly reciprocates the piston 17 fixed to the brake rod 18, which in turn actuates the brake shoe, not shown, against the wheel of the railway car 14. The coil spring 19 biases the piston 17 and the brake rod 18 to a normally brake releasing position, disclosed in FIG. 1.

Although the train line 10, auxiliary reservoir 13 and brake cylinder 16 are normally coupled directly to the corresponding ports in the triple valve 12, in this invention the novel release 20 is interposed between the triple valve 12 and its corresponding couplings to the train line 10, auxiliary reservoir 13 and brake cylinder 16 without interfering with their normal operation.

The release valve 20 includes a housing or valve body 21, including a first, or upper, auxiliary reservoir chamber 22; a second or lower auxiliary reservoir chamber 23; a train line pressure chamber 24; a check valve chamber 25; and a brake cylinder pressure chamber 26. The chambers 22-26 are arranged and interrelated in the valve body 21 substantially in the manner shown in FIG. 3. Auxiliary reservoir chamber 22 communicates with the main auxiliary reservoir 13 through the pipe or conduit 29 by any convenient means, such as threaded couplings. The upper auxiliary reservoir chamber 22 also communicates with the lower auxiliary reservoir chamber 23 through a port 30 which is adapted to be opened and closed by a reciprocating auxiliary valve 31. A valve stem 32 depends from the auxiliary valve 31 through an opening 33 in the wall 34 separating the lower auxiliary reservoir chamber 23 from the train line pressure chamber 24. The lower end of the valve stem 32 is fixed to a pressure membrane such as the piston 35, having a circumferential gasket, such as an O-ring 36, for a sealing,

yet slidable, enagement with the cylindrical wall of the I train line pressure chamber 24. The auxiliary valve 3.1 is biased to close the port 30 by means of coil spring 37 extending between the chamber wall 34 and the piston 35.

The second auxiliary reservoir chamber 23 communicates with the existing auxiliary reservoir port in the triple valve 12 through port 38.

The train line pressure chamber 24 communicates through the port 40 and the branch conduit, or pipe, 41 with the train line 10. The other side of the train line pressure chamber 24 communicates through the port 42 with the exising train line port in triple valve 12. I

The space in the train line pressure chamber 24 between the wall 34 and the piston 35 is maintained at atmospheric pressure by the vent 43 formed through the side wall of the housing 21 and communicating with the chamber 24. The valve stem opening 33 is constantly sealed by the sealing member or gasket 44.

A check valve 70 is also mounted in the wall of the train line pressure chamber 24 above the piston 35 to close the associated exhaust port (unnumbered) when the pressure in chamber 24 above piston 35 is less than atmospheric, and to open the exhaust port when the chamber pressure is greater than atmospheric.

The bottom of the check valve chamber comprises a conical seat 45 having an opening 46 in the bottom thereof communicating with brake cylinder pressure chamber 26. Adapted to reciprocate axially in the cylindrical check valve chamber 25 is a conical check valve 47 adapted to engage the conical seat 45 in its lowermost position, and in that position close the port or opening 46. The conical check valve 47 is provided with a plurality of circumferentially arranged openings, or ports, 48, adapted to permit the passage of air through the check valve 47 when the valve 47 is in a raised or unseated position. A coil spring 49 extends between the top of the check valve 47 and the wall 50 separating the check valve chamber 25 from the train line pressure chamber 24, in order to bias the check valve 47 down into seated position against the valve seat 45.

A port, or hole 52, is formed in the chamber wall 50 to permit passage of air therethrough between the train line pressure chamber 24 and the check valve chamber 25. However, the port 52 is provided with a restrictive or timing valve 53, having a small, permanent opening 54 extending therethrough, so that when the valve 53 closes the port 52, a small amount of air may still pass between chambers 24 and 25. The coil spring 55 normally biases the timing valve 53 upward to close the port 52.

The brake cylinder pressure chamber 26 communicates through an air passage 57 to another air passage 58, which connects one end of a bleeder line 59 with the existing brake cylinder port in triple valve 12. In a preferred form of the invention, the bleeder line extends from the release valve 20, first to one side of the car 14, where the line 59 includes a cutout cock 61, and then to the other side of the eat Where the bleeder line 59 includes a second cutout cock 62. The bleeder line 59 then extends into the brake cylinder 16 on the opposite side of the piston 17 from the brake rod .18. The cutout cocks 61' and 62 are provided an opposite sides of the railway car 14 in order to enable the bleeder line 59 to be closed from either side of the car, when the operation of the novel releasing mechanism is not desired. If the cutout cocks 61 and 62 are not required or needed, then an alternative bleeder line 59, as disclosed in phantom in FIG. 1, may couple the brake cylinder 16 directly with the release valve 20.

Formed transversely of the brake cylinder pressure chamber 26 is a cylindrical valve guideway 72 adapted to reciprocably receive a spool valve 73 having a reduced portion 74. One end of the guideway 72 communicates through a passage 75 with train line port 42 so that one end (the right end in FIG. 3) of the spool valve 73 is in continuous communication with train line pressure. The other end of the guideway 72 communicates through a port 77 and conduit 76 with a source of compressed air, such as the emergency exhaust port of triple valve 12, as shown in FIG. 1. Thus, when the triple valve 12 is actuated for emergency operation, the surge of compressed air, which normally exhausts to the atmosphere through the emergency exhaust port, will pass through the conduit 76 and port 77 to force the spool valve 73 toward the right of FIG. 3 causing the spool valve 73 to close fluid communication between the bleeder line air passage 57 and the brake cylinder pressure chamber 26.. In order for the spool valve 73 to move to closed position, the pressure of the air in conduit 76 must be greater than the value of the train line pressure.

As best disclosed in FIGS. 1, 2 and 4, the reserve auxiliary reservoir 13' may be coupled in a conventional manner through the conduit 64 to the regular coupling 65 of the AB valve 12. It will be noticed in FIG. 2 in this particular embodiment of the invention, the valve body 21 is cut out so that the branch line 64 is connected directly to the coupling 65 without passing through the valve body 21.

In the normal operation of the conventional railway brake system, without the brake release valve 20, the railway car 14 is coupled to other cars and to a locomotive, or switch engine, so that the compressor of the locomotive or engine is supplying the train line 10 with a normal operating pressure of approximately -130 p.s.i. Under normal operating conditions, the triple valve 12 functions to exhaust the brake cylinder 16 and close communication between the auxiliary reservoir 13 and the brake cylinder 16, to release the brakes. The train line 10 is supplied with compressed air through the engineers brake valve from the air compressor in the locomotive, not shown, in any conventional manner.

A reduction in the train line pressure of approximately 1()25 p.s.i. by operation of the brake valve, not shown, will establish communication between the auxiliary reservoir 13, pipe 29, triple valve 12, pipe 59', and brake cylinder 16 to set the brake. Unless the original operating pressure in train line 10 can be re-established, or unless the brake cylinder 16 can be exhausted in some other manner, the brakes will remain set, because pressure in the auxiliary reservoir 13 will be maintained within the brake cylinder 16. Such a condition exists when the railway car 14 is uncoupled from the other cars of the train, or from a locomotive or switch engine, so that the source of compressed air is cut oif and the train line 10 becomes exhausted.

It is therefore the purpose of applicants invention to permit the automatic release of the brakes when the railway car 14 is uncoupled, or the train line is exhausted in any other manner.

Assuming now that the release valve 20 is mounted on AB valve 12, in a manner disclosed in the drawings, and the railway car 14 is coupled through other cars to a switch engine and normal train line pressure, for example 90 p.s.i., is established in the train line 10, then the pressure in the chamber 24 is also 90 p.s.i. which forces the piston 35 upwardly to thrust upward the auxiliary valve 31 and open the port 30, so that there is normal communication between the auxiliary reservoir 13 and the triple valve 12. Moreover, the normal train line pressure in chamber 24 forces the timing valve 53 downward against spring 55 to open the port 52 so that train line pressure enters the check valve chamber 25 to assist the spring 49 in seating check valve 47 against the seat 45 to close the port 46 into the brake cylinder pressure chamber 26.

The normal train line pressure in chamber 24 is also transmitted through the port 42, passage 75 and valve guideway 72, to maintain the spool valve 73 in the open position disclosed in FIG. 3, permitting fluid communication between the brake cylinder pressure chamber 26 and the brake cylinder 16 through the lines 57, 58 and 59. As long as the normal train line pressure exists in the chamber 24 triplevalve 12 and the other elements of the railway brake mechanism, will operate in a conventional manner.

Assuming now that the railway car 14 has been uncoupled from the switch engine, and left on a siding, the train line 10 is immediately opened to the atmosphere so that the pressure in the train line 10 is rapidly reduced. As the train line pressure is reduced 10-25 p.s.i. to 80-65 p.s.i., depending upon the operating values of the particular brake mechanism, the auxiliary valve 31 remains open because the force of the train line pressure acting upon the bottom surface of piston 35 is still great enough to overcome the weight of the valve 31, valve stem 32 and piston 35 plus the force of spring 37 and atmospheric pressure exerted upon the to face of piston 35. When the train line pressure reaches 80-65 p.s.i., the triple valve 12 functions to supply the brake cylinder 16 with compressed air of about 55 p.s.i. from the auxiliary reservoirs 13 and 13 through the line 59 or 59, to force the piston 17 to the right, as disclosed in FIG. 1, to immediately set the brakes. Further reduction of train line pressure in chamber 24 will permit the spring 37 to force piston 35 downward until the auxiliary valve 31 closes port 30, so that the pressure in the auxiliary reservoir 13 will be maintained while car 14 is uncoupled and even after the brakes have been released. In the meantime, reserve auxiliary reservoir 13' will continue to supply air under pressure to brake cylinder 16 through conduit 64, triple valve 12 and pipe 59 or 59 until pressure equilibrium is established.

After the force of spring 37 overcomes the train line ressure exerted upon the piston 35, the downward movement of the piston 35, and consequently the auxiliary valve 31, will be retarded because of the vacuum created within the train line pressure chamber 24 above the piston 35. This vacuum will automatically cause check valve 70 to close the exhaust port. Of course, the vacuum above the piston 35 will gradually be neutralized by the supply of atmospheric air through the small by-pass vent 43. Thus, the degree of retarded movement of the piston 35 and the closing of the auxiliary valve 31 will depend upon the size of the vent 43. The purpose of this retarded movement is to provide an ample supply of compressed air from the auxiliary reservoir 13 to the brake cylinder 16 after the triple valve 12 has been actuated by the normal reduction in the train line pressure. In other words, if the supply of air to the brake cylinder 16 from the auxiliary reservoir 13 is cut off too soon by the closing of the auxiliary valve 31, the brake mechanism will not be properly set.

When the train line pressure 10 is reduced below the pressure in the brake cylinder 16, and consequently in the brake cylinder pressure chamber 26, plus the value of the spring 49 and the weight of the check valve 47, the brake cylinder pressure forces the check valve 47 upward to disengage the conical seat 45 and permit the air in the brake cylinder 16 and chamber 26 to discharge through the ports 48 and into the chamber 25. Since the pressure in the chamber 25 exceeds the train line pressure in chamber 24, the timing valve 53 remains seated to close the port 52, so that air from the chamber 25 can discharge into the chamber 24 only through the very small-diameter hole 54. Thus, the air from brake cylinder 16 is slowly and gradually discharged through the bleeder line 59, passage 58, passage 57, chamber 26, ports 48, chamber 25, and hole 54, into the chamber 24 and out through port 40 and pipe 41 to the train line 10. Eventually, as the pressure in the brake cylinder 16 is gradually reduced, the spring 19 will force the piston 17 toward the left of the cylinder 16 to release the brakes. The time required for this gradual release of the brakes depends on the diameter of the hole 54. For example, a hole of .001 inch diameter will permit the brakes to remain set for about minutes before being released.

The diameter of the hole 54 in the timing valve 53 may be of different sizes to vary the length of time the brakes on the uncoupled car 14 will remain set. Thus, with the release valve 20, a car 14 can be uncoupled, have its brakes automatically set, and then, at the appropriate time, the brakes will automatically release so that the uncoupling, re-routing and recoupling to another train can be effected without manually releasing the brakes.

It will, of course, be understood that during the normal operation of the release valve 20, bot-h cutout cocks 61 and 62 will remain open. If the car 14, after it is un coupled, is destined to remain on a siding for a period longer than the timing of the valve 53, then either the cutout cock 61 or 62 may be closed so that the brakes will remain set indefinitely.

Instead of using the cutout cocks 61 or 62 to set the brakes indefinitely, the brake-holding valve 73 may be automatically positioned to close communication between the brake cylinder pressure chamber 25 and the bleeder passage 57, and consequently the bleeder line 59. The brake-holding valve 73 may be set by turning the brake valve, not shown, to emergency position, which will automatically and simultaneously rapidly reduce the train line pressure to actuate the triple valve for emergency operation. The reduction in train line pressure is transmitted to the right end of valve guideway 73. Simultaneously, a surge of compressed air discharges from the emergency exhaust port of the triple valve 12 through line 76 to the left side of the spool valve 73. Thus, even after the car 14 is uncoupled from the train, the spool valve 73 will remain in the closed position so that the brakes will remain set indefinitely. After the car 14 is coupled again to the locomotive or to the other cars, and normal pressure is restored to the train line 10', the spool valve 73 will be returned to its open position disclosed in FIG. 3.

It is thus seen that a novel but simple valve means has been provided in a conventional railway brake system for automatically releasing the brakes when the train line is uncoupled and opened to the atmosphere. The novel brake release means is only operative when the pressure in the train line is reduced and the brake mechanism can no longer be controlled. Moreover, when this brake release device is employed in a railway brake system, it will not only release the brakes simultaneously in a train of isolated uncoupled cars, but will also eliminate the slow laborious process of manually releasing the brakes in each car individually. Thus, in train operations such as humping, this device will eliminate the delay in releasing the brakes and preparing the train for switching operations.

What is claimed is:

1. In a railway air brake system, including a brake mechanism, a brake cylinder for actuating said brake mechanism, a train line, a triple valve, an auxiliary reservoir, an auxiliary line connecting said auxiliary reservoir and said triple valve in fluid communications, and means for maintaining normal operating pressure in said train line and for reducing the pressure in said train line to actuate said triple valve and said auxiliary reservoir to increase the pressure in said brake cylinder for actuating said brake mechanism, a brake releasing device comprising:

(a) a bleeder line communicating said train line with said brake cylinder,

(b) a check valve in said bleeder line normally closing said bleeder line when said train line pressure is normal, and opening said bleeder line to exhaust said brake cylinder when said train line pressure has been reduced to a predetermined value below the pressure in said brake cylinder,

(c) an auxiliary valve in said auxiliary line and responsive to train line pressure, said auxiliary valve normally opening said auxiliary line when said train line pressure is of a value at least sufficient to actuate said triple valve, said auxiliary valve closing said auxiliary line when said train line pressure is less than said value for actuating said triple valve.

2. The invention according to claim 1 in which said brake releasing device further comprises a valve body, said check valve and said auxiliary valve being in said valve body.

3. The invention according to claim 2 further comprising a timing valve in said valve body restricing the fiow of air from said brake cylinder to said train line when said check valve opens said bleeder line.

4. The invention according to claim 3 in which said timing valve has a permanent hole therethrough permitting the passage of air from said brake cylinder'to said train line when said check valve is open, the size of said opening being of a predetermined value depending upon the desired time for exhausting said brake cylinder.

5. The invention according to claim 2 in which said valve body comprises an auxiliary reservoir chamber, a train line chamber, and a brake cylinder chamber, each of said chambers extending through said valve body as portions of said auxiliary line, said train line and said bleeder line, respectively, and communicating with said triple valve, a check valve chamber in said valve body communicating said brake cylinder chamber with said train line chamber, said check valve chamber receiving said check valve, means in said check valve chamber normally biasing said check valve to a position closing communication between said brake cylinder chamber and said check valve chamber, said check valve being adapted to be moved to a position opening communication between said brake cylinder chamber and said check valve chamber when said brake cylinder pressure exceeds the train line pressure plus the value of said biasing means, said auxiliary valve being operatively received in said auxiliary reservoir chamber.

6. The invention according to claim 5 in which said auxiliary valve is connected to a pressure membrane in said train line chamber responding to the train line pressure to open and close said auxiliary valve.

7. The invention according to claim 5 comprising means for retarding the closing of said auxiliary valve even when said train line pressure is less than said value for actuating said triple valve.

8. The invention according to claim 6 further comprising a membrane chamber for reciprocably receiving said pressure membrane in air-sealed engagement with said membrane chamber, an exhaust port having a check valve and a by-pass vent in said membrane chamber to permit free movement of said membrane in the direction to open said auxiliary valve and to retard movement of said auxiliary valve in the opposite direction to close said auxiliary valve.

9. The invention according to claim 1 further comprising a brake-holding valve in said bleeder line between said check valve and said brake cylinder, said brake-holding valve being responsive to said train line pressure for maintaining said brake-holding valve in a position to open said bleeder line when said train line pressure is above a predetermined value, a source of compressed air, said brake-holding valve being responsive to the air pressure in said source for moving said brakeholding valve to a position closing said bleeder line when said train line pressure is substantially less than norm-a1.

10. The invention according to claim 9 in which said brake-holding valve comprises a spool valve adapted to transversely reciprocate to open and close said bleeder line, one end of said spool valve being in communication with said train line pressure, and the other end of said spool valve being in communication with said source of compressed air.

References Cited UNITED STATES PATENTS 6/1936 Hewitt 30372 X 8/1942 Sudduth 30368 

